The 24-year-old has moved to Turin until June 2013, with the Serie A champions retaining an option to buy the player at the end of his temporary spell with the club
The Denmark international has been linked with a move to Turin over the last few days as the Serie A champions failed in their bid to land Manchester United striker Dimitar Berbatov, who has since joined Premier League side Fulham.
Bendtner, who spent last season on loan at Sunderland, was identified as an alternative to the Bulgarian striker and he has now completed a move to the Old Lady, who retain an option to buy the player at the end of the season.
A statement on the club's official website read: "Nicklas Bendtner is a Juventus player.
"Juventus have reached an agreement with Arsenal for the temporary acquisition, with option rights, for the 24-year-old Danish born attacker.
"The former Gunner has signed a contract until June 30, 2013."
Juventus are believed to have pipped Siena to Bendtner's signature, according to the club's sporting director Stefano Antonelli.
Bendtner becomes the club's second deal this week after goalkeeper Rubinho joined from fellow Serie A side Palemo.